Module 8: Nutrients Important for Antioxidant Activity and Vision: Objectives

Question 1

Describe free radicals.

Answer 1

Free radicals, unstable molecules with unpaired electrons, are an unavoidable byproduct of cellular metabolism. Free radicals can steal electrons from lipids, proteins, RNA, and DNA, causing them damage.

Question 2

Identify various free radical detoxifying enzymes and antioxidants.

Answer 2

Enzymes-
Superoxide Dismutases (SOD)
Catalase
Glutathione Peroxidases.

Antioxidants-
Glutathione
Uric Acid

Question 3

Explain oxidative stress and identify diseases associated with oxidative stress.

Answer 3

Oxidative stress occurs when there is an imbalance between free radical production and detoxification. Sustained oxidative tissue damage that can contribute to disease occurs only when free radical detoxification systems and repair systems are overwhelmed. Free radical-induced damage, when left unrepaired, destroys lipids, proteins, RNA, and DNA, and can contribute to disease. Oxidative stress has been implicated as a contributing factor to cancer, heart disease, arthritis, diabetes, kidney disease, Alzheimer’s disease, cataracts, Parkinson’s disease, and aging.

Question 4

List the antioxidant nutrients and describe their functions.

Answer 4

Vitamin E-The primary function of Vitamin E is as an antioxidant. Alpha-tocopherol and vitamin E’s other constituents are primarily responsible for protecting cell membranes against lipid destruction caused by free radicals.

Vitamin C-Vitamin C’s ability to easily donate electrons makes it a highly effective antioxidant. It protects lipids both by disabling free radicals and by aiding in the regeneration of vitamin E. In addition to its role as an antioxidant, vitamin C is a required part of several enzymes involved in the synthesis of collagen, signaling molecules in the brain (neurotransmitters), some hormones, bile, and amino acids. Vitamin C also reduces formation of nitrosamines (cancer-causing agents in some cured and processed meats).

Question 5

Give examples of good food sources of antioxidant nutrients.

Answer 5

vitamin e-
sunflower seeds
almonds
sunflower oil
hazelnut
peanut butter
Wheat germ oil

vitamin c-
peppers
orange juice
grapefruit juice
strawberries
broccoli
cantaloupe

Question 6

Describe the functions of Vitamin A.

Question 7

Give examples of good food sources of Vitamin A.

Question 8

Describe the development of cancer.

Question 9

Identify risk factors for cancer.